Indolizidine alkaloids as a class of heterocycles are well represented in the area of medicinal chemistry, acting on a number of targets including glucosidases, T-cell fusion helper cells, etc. with the potential treatment of HIV, diabetes, cancer, and obesity. Ring closing metathesis (“RCM”) a powerful method for carbon-carbon bond formation and the utility of ring closing metathesis has expanded in the recent past and has become a well-recognized synthetic strategy for both carbocycles and heterocycles. Towards our attempt to synthesize a number of analogs with the indolizidine scaffold with various functionalities we were interested in developing a synthetic route that does not rely on a carbohydrate as the starting synthon. The process of this invention provides a synthetic sequence that utilizes the RCM for the construction of functionalized indolizidines from proline.
The following experimental details are set forth to aid in an understanding of the invention, and are not intended, and should not be construed to limit in any way the invention set forth in the claims that follow thereafter.